Nationwide changes should be made to the way care placements are managed, a report has said, after an inquiry into the "cruel" mistreatment of residents at a care home for autistic adults.
Mendip House, near Highbridge, Somerset, was closed in November 2016 after whistleblowers made abuse allegations and the home was branded "inadequate" by inspectors from the Care Quality Commission.
It was home to six people with autism and was one of seven separately registered dwellings on a residential care home campus known as Somerset Court, run by the National Autistic Society.
After the closure the Somerset Safeguarding Adults Board commissioned a safeguarding adults review into events at Mendip House.
The inquiry found there was a "sustained failure to address the taunting, mistreatment and humiliation of residents" and that Mendip House was "dominated by a 'gang' of controlling male staff".
Allegations included a member of staff bringing a games console into work, racist and sexual comments made to staff and one resident made to crawl around on all fours.
Staff also threw cake at a resident's head while another was given a raw onion to eat, and when they refused they were sent to their room.
An audit found that for two years residents had been paying for the meals of staff accompanying them on outings. Almost £10,000 was reimbursed to six residents.
The inquiry noted: "The staff at Mendip House engaged in behaviour that was cruel, far below the standard expected."
Six members of staff, including the manager and deputy, were dismissed and the review highlighted weaknesses in the system by which authorities making care placements outside their local area monitored the care provided.
The recommendations include the Department of Health and Social Care, NHS England and the Local Government Association carrying out a national consultation on steps to regulate the commissioning of care placements.
At the time, Somerset Court was home to 42 adults with severe autism placed by 26 local authorities and four clinical commissioning groups from across the UK.
The report said: "Somerset County Council has no enthusiasm for placing adults with autism at Somerset Court.
"Yet it had to invest in an expensive and labour-intensive inquiry because of the lack of rigor and failures of judgment of commissioning professionals.
"Since commissioners are responsible and accountable, arguably it is only a matter of time before they are prosecuted."
It also recommends that the CQC makes clear in its inspection reports that it will no longer register "campus" model care arrangements and that commissioners should be required to notify the local authority in the area a placement is being made.
Richard Crompton, chairman of Somerset Safeguarding Adults Board, said: "These reviews are not about apportioning blame, they are about making sure lessons are learned and improvements made.
"This happened to be in Somerset, but the weaknesses in the system are nationwide and must be considered at that level.
"That is why some of our key recommendations are addressed to the Department of Health and Social Care and national bodies.
"I know that the agencies involved have learned lessons and I hope that they can be learned nationally too."
In 2011 the now notorious Winterbourne View hospital near Bristol was shut down after an undercover investigation exposed physical and psychological abuse.
Last year 13 directors, managers and carers were convicted over a regime at residential homes in Devon run by Atlas Project Team in which adults with learning disabilities were imprisoned in isolation rooms.